This week's candidate for piscine peculiarity status is the familiarly freakish Sawfish (Pristis pectinata), subject of endless interest due to its remarkable rostrum.
Despite their initial resemblance to sharks, these extraordinary elasmobranchs are most closely related to rays.
Their distinctive saw-edged snout is edged with tooth like structures known as denticles, and in combination with a highly refined array of electro receptors along its length this peculiar proboscis is a deadly tool for seeking out prey.
Sawfish are typically languid swimmers, but once they detect potential food swimming nearby or hidden under the substrate they lash out with a slashing motion of their head, stunning, injuring or killing anything unfortunate enough to get in the way, then snapping it up with their under-slung mouth.
The scientific name 'Pristis' is another reference to their unusual nose meaning 'saw' in Greek.
They are surprisingly large, with mature specimens topping 7.5m/25' in length but are generally gentle giants, only being a risk to humans if hooked or when entangled in nets.
The Smalltooth sawfish is considered critically endangered throughout its entire range within the tropical and subtropical waters of the Atlantic and is now thought to be extinct in many areas where it was once found such as the Mediterranean.
Sadly, all other known Sawfish are also listed as critically endangered and the whole picture is further muddied by considerable confusion about the true taxonomic status of many of the described species, with only four being considered valid at present. This situation isn't helped by the rarity of the remaining specimens which means that tissue samples and other material that could be used to clarify the Pristiformes is seldom available.
Commercial fishing of the species is not banned in many countries, despite its precarious status, but the depleted remaining population means that targeted fishing of the species is impossible and the majority are now caught accidentally as bycatch as they become easily entangled in nets.
Their saws are sought-after curios while their fins are prized for the shark fin trade.
The preferred shallow coastal habitat of Sawfish is vulnerable to pollution and from human activities such as mangrove clearance, coastal development.
The only positive news for the species, and for Sawfish in general is that some former strongholds are now included in marine reserves, while new legislation in gill net use in other areas may also benefit them long term.
CITES, (Convention on International Trade in Endangered Species of Wild Fauna and Flora) also lists Pristis pectinata on its Appendix I which makes trade in wild caught specimens illegal within countries that recognise the agreement.
Take a look at the video below which shows wild footage of the Smalltooth sawfish.
Why not take a look at some of our other Weird fish of the week features?
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